Centrifugal fan

The invention discloses a centrifugal fan. The centrifugal fan comprises a motor, a volute, an impeller which is arranged on the volute, and a front plate which is arranged on the impeller, wherein acircular sunken part is arranged in a circle on the inner wall, far away from one side of the motor, of the volute; the diameter of the annular sunken part is beyond the diameter of the impeller. Withthe adoption of the centrifugal fan, air is prevented from flowing close to the front plate of the impeller along the wall surface of the volute, thus the air flowing back to an inlet of the impellerthrough a gap between the front plate of the impeller and the volute decreases, and as a result, the purposes of improving the fan efficiency and reducing the noise can be achieved. 本发明公开了种离心风机，包括电机、蜗壳、设置在蜗壳上的叶轮以及设置在叶轮上的前盘，远离电机侧的蜗壳内壁设置有周环形凹陷，所述环形凹陷的直径大于叶轮的直径，本发明抑制气流沿着蜗壳的壁面流向叶轮的前盘附近，使通过叶轮前盘和蜗壳的间隙流回叶轮进口的气流减小，从而达到提升风机效率，降低噪音的目的。